Recent advances of transformable nanoparticles for theranostics

Dual delivery of carbon monoxide and doxorubicin using haemoglobin-albumin cluster: proof of concept for well-tolerated cancer therapy

A serious concern of doxorubicin (DOX) therapy is that it causes severe adverse effects, particularly cardiotoxicity. Carbon monoxide (CO) possesses powerful cytoprotective effects against drug-induced organ injury and is expected to ameliorate DOX-induced cardiotoxicity. In this study, a dual carrier of DOX and CO (CO-HemoAct-DOX) was fabricated based on a haemoglobin-albumin cluster (HemoAct), which is a protein cluster with a haemoglobin core structure wrapped by serum albumin. CO-HemoAct-DOX was synthesised by binding CO to a haemoglobin core and covalently conjugating (6-maleimidocaproyl)hydrazone derivative of DOX to an albumin shell. The average DOX/cluster ratio was about 2.6. In the in vitro cytotoxicity assay against cancer cells, the anti-tumour activity of CO-HemoAct-DOX was 10-fold lower than that of DOX in a 2D-cultured model, whereas CO-HemoAct-DOX suppressed the growth of tumour spheroids to the same extent as DOX in the 3D-cultured model. In colon-26 tumour-bearing mice, CO-HemoAct-DOX achieved DOX delivery to the tumour site and alleviated tumour growth more effectively than DOX. Furthermore, CO-HemoAct attenuated DOX-induced cardiomyocyte atrophy in H9c2 cells and elevated the levels of cardiac biomarkers in mice exposed to DOX. These results suggest that the dual delivery of CO and DOX using HemoAct is a promising strategy as an anti-tumour agent to realise well-tolerated cancer therapy with minimal cardiotoxicity.

Advances in nanotechnology for improving the targeted delivery and activity of amphotericin B (2011-2023): a systematic review

Amphotericin B (AmB) is a broad-spectrum therapeutic and effective drug, but it has serious side effects of toxicity and solubility. Therefore, reducing its toxicity should be considered in therapeutic applications. Nanotechnology has paved the way to improve drug delivery systems and reduce toxicity. The present study, for the first time, comprehensively reviews the studies from 2011 to 2023 on reducing the in vitro toxicity of AmB. The findings showed that loading AmB with micellar structures, nanostructured lipid carriers, liposomes, emulsions, poly lactide-co-glycolide acid, chitosan, dendrimers, and other polymeric nanoparticles increases the biocompatibility and efficacy of the drug and significantly reduces toxicity. In addition, modified carbon nanoparticles (including graphene, carbon nanotubes, and carbon dots) with positively charged amine groups, PEI, and other components showed favorable drug delivery properties. Uncoated and coated magnetic nanoparticles and silver NPs-AmB composites had less cytotoxicity and more antifungal activity than free AmB. Citrate-reduced GNPs and lipoic acid-functionalized GNPs were also effective nanocarriers to reduce AmB cytotoxicity and improve anti-leishmania efficacy. In addition, zinc oxide-NPs and PEGylated zinc oxide-NPs showed favorable antifungal activity and negligible toxicity. According to a review study, carbon-based nanoparticles, metal nanoparticles, and especially polymer nanoparticles caused some reduction in the toxicity and improved solubility of AmB in water. Overall, considering the discussed nanocarriers, further research on the application of nanotechnology as a cost-effective candidate to improve the efficiency and reduce the cytotoxicity of AmB is recommended.

Reactive oxygen species-responsive nanocarrier ameliorates murine colitis by intervening colonic innate and adaptive immune responses

Ulcerative colitis (UC) is a chronic or relapsing inflammatory disease with limited therapeutic outcomes. Pterostilbene (PSB) is a polyphenol-based anti-oxidant that has received extensive interest for its intrinsic anti-inflammatory and anti-oxidative activities. This work aims to develop a reactive oxygen species (ROS)-responsive, folic acid (FA)-functionalized nanoparticle (NP) for efficient PSB delivery to treat UC. The resulting PSB@NP-FA had a nano-scaled diameter of 231 nm and a spherical shape. With ROS-responsive release and ROS-scavenging properties, PSB@NP could effectively scavenge H2O2, thereby protecting cells from H2O2-induced oxidative damage. After FA modification, the resulting PSB@NP-FA could be internalized by RAW 264.7 and Colon-26 cells efficiently and preferentially localized to the inflamed colon. In dextran sulfate sodium (DSS)-induced colitis models, PSB@NP-FA showed a prominent ROS-scavenging capacity and anti-inflammatory activity, therefore relieving murine colitis effectively. Mechanism results suggested that PSB@NP-FA ameliorated colitis by regulating dendritic cells (DCs), promoting macrophage polarization, and regulating T cell infiltration. Both innate and adaptive immunity were involved. More importantly, the combination of the PSB and dexamethasone (DEX) enhanced the therapeutic efficacy of colitis. This ROS-responsive and ROS-scavenging nanocarrier represents an alternative therapeutic approach to UC. It can also be used as an enhancer for classic anti-inflammatory drugs.

Mechanisms of deformation and drug release of targeting polypeptides based on fibronectin induction

Polypeptide nano-carriers with deformation and sustained-release function have gained an attention in anti-tumor treatment. A multifunctional polypeptide with different motifs was discussed and the contribution of each motif to targeted drug release was analyzed by control studies. The transformation and drug release processes of polypeptides were investigated by molecular dynamics method to reveal their dynamics mechanism, and corresponding experiments were performed to verify the simulation results. We observed that the polypeptides could form NPs under the hydrophobic interaction between self-assembly motifs and the electrostatic repulsion between targeting motifs. Affected by the ligand-receptor interaction, the targeting motifs overcame the electrostatic repulsion to approach the ligand proteins, leading to the promotion of the binding of fibrous motifs and the transformation of NPs into NFs for better retention of drugs in the tumor tissues. In addition, the polypeptides with strong hydrophobicity exhibited excellent sustained-release efficiency. These insights allow drawing general conclusions contributed to the design of transformable polypeptide NPs: The decrease in the hydrophobicity of self-assembly motifs is beneficial for the enrichment of doxorubicin in tumor tissues, as well as the similar result can be obtained with the improvement of the hydrophobicity of fibrous motifs and the capability of target.

Dual-Stage Irradiation of Size-Switchable Albumin Nanocluster for Cascaded Tumor Enhanced Penetration and Photothermal Therapy

The triple-negative breast cancer (TNBC) microenvironment makes a feature of aberrant vasculature, high interstitial pressure, and compact extracellular matrix, which combine to reduce the delivery and penetration of therapeutic agents, bringing about incomplete elimination of cancer cells. Herein, employing the tumor penetration strategy of size-shrinkage combined with ligand modification, we constructed a photothermal nanocluster for cascaded deep penetration in tumor parenchyma and efficient eradication of TNBC cells. In our approach, the photothermal agent indocyanine green (ICG) is laded in human serum albumin (HSA), which is cross-linked by a thermally labile azo linker (VA057) and then further modified with a tumor homing/penetrating tLyP-1 peptide (HP), resulting in a TNBC-targeting photothermal-responsive size-switchable albumin nanocluster (ICG@HSA-Azo-HP). Aided by the enhanced permeability and retention effect and guidance of HP, the ca. 149 nm nanoclusters selectively accumulate in the tumor site and then, upon mild irradiation with the 808 nm laser, disintegrate into 11 nm albumin fractions that possess enhanced intratumoral diffusion ability. Meanwhile, HP initiates the CendR pathway among the nutrient-deficient tumor cells and facilitates the transcellular delivery of the nanocluster and its disintegrated fractions for subsequent therapy. By employing this size-shrinkage and peptide-initiated transcytosis strategy, ICG@HSA-Azo-HP possesses excellent penetration capabilities and shows extensive penetration depth in three-dimensional multicellular tumor spheroids after irradiation. Moreover, with a superior photothermal conversion effect, the tumor-penetrating nanocluster can implement effective photothermal therapy throughout the tumor tissue under a second robust irradiation. Both in vivo orthotopic and ectopic TNBC therapy confirmed the efficient tumor inhibition of ICG@HSA-Azo-HP after dual-stage irradiation. The synergistic penetration strategy of on-demanded size-shrinkage and ligand guidance accompanied by clinically feasible NIR irradiation provides a promising approach for deep-penetrating TNBC therapy.

Delivery strategies of amphotericin B for invasive fungal infections

Invasive fungal infections (IFIs) represent a growing public concern for clinicians to manage in many medical settings, with substantial associated morbidities and mortalities. Among many current therapeutic options for the treatment of IFIs, amphotericin B (AmB) is the most frequently used drug. AmB is considered as a first-line drug in the clinic that has strong antifungal activity and less resistance. In this review, we summarized the most promising research efforts on nanocarriers for AmB delivery and highlighted their efficacy and safety for treating IFIs. We have also discussed the mechanism of actions of AmB, rationale for treating IFIs, and recent advances in formulating AmB for clinical use. Finally, this review discusses some practical considerations and provides recommendations for future studies in applying AmB for combating IFIs.

Size-Transformable Nanostructures: From Design to Biomedical Applications

The size of nanostructures (NSs) strongly affects their chemical and physical properties and further impacts their actions in biological systems. Both small and large NSs possess respective advantages for disease theranostics, and this therefore presents a paradox when choosing NSs with suitable sizes. To overcome this challenge, size-transformable NSs have emerged as a powerful tool, as they can be manipulated to possess the merits of both types of NSs. Herein, various strategies to construct size-transformable NSs are summarized, and the recent research progress regarding their biomedical applications, particularly within the fields of cancer and bacterial theranostics, is highlighted. This review will inspire researchers to further develop various methods that can be used to construct size-transformable NSs for use in novel applications within different fields.

The application of nitric oxide delivery in nanoparticle-based tumor targeting drug delivery and treatment

Nitric oxide (NO) shows great role in tumor biology. Recent years, more and more researches utilized NO donor in tumor targeting drug delivery and treatment. In this review, we summarized the NO donors by their endogenous and exogenous stimuli. Then the application of NO donors, which was the main aim of the review, was discussed in detailed according to their functions, including inducing tumor cell apoptosis, reversing tumor multidrug resistance, inhibiting tumor metastasis and improving drug delivery.

Sequentially responsive biomimetic nanoparticles with optimal size in combination with checkpoint blockade for cascade synergetic treatment of breast cancer and lung metastasis

Recently, photodynamic therapy (PDT) emerges as a promising way to initiate immune response and being used in combination with chemotherapy. However, the antitumor effect is restricted due to the poor tumor penetration and retention, premature drug release and immunosuppressive environment of tumor sites. And as the size of nanoparticles plays a key role in drug delivery, series of hyaluronidase-responsive size-reducible biomimetic nanoparticles (mCAuNCs@HA) with different initial sizes are synthesized, and the optimal size of 150 nm is screened out because of the best blood circulation, tumor penetration and retention. Then the photosensitizer pheophorbide A and ROS-responsive paclitaxel dimer prodrug (PXTK) are co-loaded to facilitate on-demand drug release. The hydrolysis byproduct cinnamaldehyde in turn stimulates the ROS production by mitochondria, which compensates for the ROS consumed in the hydrolysis process. Anti-PD-L1 peptide (dPPA) is furthered loaded to alleviate the immunosuppressive environment of tumor and enhance the function of cytotoxic T lymphocytes activated by PDT-induced immunogenic cell death. The combination therapy activates CD4⁺, CD8⁺ T cells and NK cells and enhances secretion of cytokines (TNF-α and IL-12) with tumor inhibition rate increased to 84.2% and no metastasis is observed, providing a viable combination therapy for better anti-tumor and anti-metastasis efficacy.

Controlled co-precipitation of biocompatible colorant-loaded nanoparticles by microfluidics for natural color drinks

Natural colorants, which impart a vivid color to food and add additional health benefits, are favored over synthetic colorants; however, their applications are limited by their low solubility in water and low stability. Here, we develop a versatile microfluidic strategy to incorporate natural colorants in shellac nanoparticles with controlled physicochemical properties. The rapid mixing in the microfluidic channels ensures that the mixing time is shorter than the aggregation time, thus providing control over the co-precipitation of the colorant and the polymer. By introducing molecular interactions, colorant nanoaggregates are efficiently embedded in the polymer matrix, forming hierarchical colorant-loaded nanoparticles. The colorant-loaded nanoparticles dispersed in water are transparent and stable over a wide pH range and their polymer matrix also provides a favorable microenvironment that greatly improves the shelf life of the colorants. The improved solubility, stability and bioavailability of the natural colorants suggest that shellac nanoparticles are ideal carriers and the stable, transparent dispersions of biocompatible colorant-loaded nanoparticles in water are well-suited for the development of functional foods, such as natural color drinks.

Theranostic nanoparticles with tumor-specific enzyme-triggered size reduction and drug release to perform photothermal therapy for breast cancer treatment

Although progress has been indeed made by nanomedicines, their efficacies for cancer treatment remain low, consequently leading to failures in translation to clinic. To improve the drug delivery efficiency, nanoparticles need to change size so as to fully utilize the enhanced permeability and retention (EPR) effect of solid tumor, which is the golden principle of nanoparticles used for cancer treatment. Herein, we employed cationic small-sized red emission bovine serum albumin (BSA) protected gold nanocluster (AuNC@CBSA, 21.06 nm) to both load indocyanine green (ICG) and act as imaging probe to realize theranostic. Then AuNC@CBSA-ICG was fabricated with negatively charged hyaluronic acid (HA) to form AuNC@CBSA-ICG@HA, which was about 200 nm to easily retain at tumor site and could be degraded by tumor-specific hyaluronidase into small nanoparticles for deep tumor penetration. The HA shell also endowed AuNC@CBSA-ICG@HA with actively targeting ability and hyaluronidase-dependent drug release. Furthermore, the quenching and recovery of fluorescence revealed the interaction between ICG and carrier, which was essential for the investigation of pharmacokinetic profiles. No matter in vitro or in vivo, AuNC@CBSA-ICG@HA showed markedly anti-tumor effect, and could suppress 95.0% of tumor growth on mice breast cancer model. All results demonstrated AuNC@CBSA-ICG@HA was potential for breast cancer therapy.

Redox/pH dual-stimuli responsive camptothecin prodrug nanogels for "on-demand" drug delivery

At present, chemotherapy remains to be one of the most important therapeutic approaches for malignant tumors. The tumor microenvironment(TME)-responsive intelligent drug delivery systems are still the hot research topics in delivering chemotherapeutic drugs. Camptothecin (CPT) possesses very strong antitumor activities, but its clinical application is hindered by its poor water-solubility and serious toxic side effects. Herein, a new intelligent and TME-responsive P(CPT-MAA) prodrug nanogel was developed for delivering CPT and reducing its side effects. P(CPT-MAA) prodrug nanogels were prepared with methacrylic acid (MAA), CPT monomer (CPTM) and N,N'-methylenebisacrylamide (Bis) via distillation-precipitation polymerization, in which CPT was covalently conjugated into the nanogels via redox-responsive disulfide linker. The as-prepared nanogels were spherical shapes with uniform size and narrow size distribution. With the help of redox-responsive property of disulfide linker and pH-responsive property of PMAA, the release of CPT from prodrug nanogels was redox/pH-dual dependent and could be accelerated by the increased concentration of GSH and the decreased pH value, which were favorable to realize the "on-demand" drug release in tumor cell and tumor tissue microenvironment. Furthermore, P(CPT-MAA) prodrug nanogels exhibited superior antitumor activity both in vitro and in vivo without observed side effects. Hence, the prepared P(CPT-MAA) prodrug nanogels may be a promise delivery system for chemotherapeutic agents.

In vivo tailor-made protein corona of a prodrug-based nanoassembly fabricated by redox dual-sensitive paclitaxel prodrug for the superselective treatment of breast cancer

Prodrug self-nanoassemblies have many advantages for anticancer drug delivery, including high drug loading rate, resistance to recrystallization, and on-demand drug release. However, few studies have focused on their protein corona, which is inevitably formed after entering the blood and determines their subsequent fates in vivo. To actively tune the protein corona of prodrug nanoassemblies, three maleimide-paclitaxel prodrugs were synthesized via different redox-sensitive linkers (ester bond, thioether bond and disulfide bond). After incubation with rat plasma, the surface maleimide groups effectively captured albumins, resulting in albumin-enriched protein corona. The recruited albumin corona enabled enhanced tumor accumulation and facilitated cellular uptake, ensuring the high-efficiency delivery of nanoassemblies to tumor cells. Surprisingly, we found that the traditionally reduction-sensitive disulfide bond could also be triggered by reactive oxygen species (ROS). Such a redox dual-responsive drug release property of the disulfide bond-containing prodrug nanoassemblies further increased the selectivity in cytotoxicity between normal and tumor cells. Moreover, the disulfide bond-containing prodrug nanoassemblies exhibited the highest antitumor efficacy in vivo compared to marketed Abraxane® and other prodrug nanoassemblies. Thus, the fabrication of the maleimide-decorated disulfide bond bridged prodrug nanoassembly, integrating a tunable protein corona and on-demand drug release, is a promising strategy for improved cancer chemotherapy.

Self-Assembled Fluorescent Organic Nanomaterials for Biomedical Imaging

Fluorescent nanomaterials, self-assembled from building blocks through multiple intermolecular interactions show diversified structures and functionalities, and are potential fluorescence contrast agents/probes for high-performance biomedical imaging. Self-assembled nanomaterials exhibit high stability, long circulation time, and targeted biological distribution. This review summarizes recent advances of self-assembled nanomaterials as fluorescence contrast agents/probes for biomedical imaging. The self-assembled nanomaterials are classified into two groups, i.e., ex situ and in situ construction of self-assembled nanomaterials. The advantages of ex situ as well as in situ constructed nanomaterials for biomedical applications are discussed thoroughly. The directions of future developments for self-assembled nanomaterials are provided.

In situ construction of nanonetworks from transformable nanoparticles for anti-angiogenic therapy

Tumor metastasis as the most common reason of death from cancer has always been a great challenge in both clinical and scientific research, where angiogenesis plays a necessary role. Herein, we report an extracellularly transformable nanomaterial for in situ construction of defensive networks on interaction with vascular endothelial growth factor (VEGF) for anti-angiogenic therapy of tumor. The fibrous networks exhibit transformation-enhanced accumulation and retention (TEAR) effects (over 72 h), and bind and intercept cell-secreted VEGF over particulate and molecular anti-angiogenic agents with high efficiency, leading to anti-angiogenesis. This study demonstrates that angiogenesis is positively related to tumor growth as well as tumor metastasis; the anti-angiogenic therapy inhibits tumor metastasis with an inhibition rate of 65.9%. In addition, this extracellular strategy of transformation may be utilized to bind huge amounts of cell-secreted biomolecules/factors or receptors on cell surfaces and inhibit their functionalities for cancer therapy.

Coadministration of iRGD with Multistage Responsive Nanoparticles Enhanced Tumor Targeting and Penetration Abilities for Breast Cancer Therapy

Limited tumor targeting and poor penetration of nanoparticles are two major obstacles to improving the outcome of tumor therapy. Herein, coadministration of tumor-homing peptide iRGD and multistage-responsive penetrating nanoparticles for the treatment of breast cancer are reported. This multistage-responsive nanoparticle, IDDHN, was comprised of an NO donor-modified hyaluronic acid (HN) shell and a small-sized dendrimer, namely, dendri-graft-l-lysine conjugated with doxorubicin and indocyanine (IDD). The results showed that IDDHN could be degraded rapidly from about 330 nm to a smaller size that was in a size range of 35 to 150 nm (most at 35-60 nm) after hyaluronidase (HAase) incubation for 4 h; in vitro cellular uptake demonstrated that iRGD could mediate more endocytosis of IDDHN into 4T1 cells, which was attributed to the overexpression of α_vβ₃ integrin receptor. Multicellular spheroids penetration results showed synergistically enhanced deeper distribution of IDDHN into tumors, with the presence of iRGD, HAase incubation, and NO release upon laser irradiation. In vivo imaging indicated that coadministration with iRGD markedly enhanced the tumor targeting and penetration abilities of IDDHN. Surprisingly, coadministration of IDDHN with iRGD plus 808 nm laser irradiation nearly suppressed all tumor growth. These results systematically revealed the excellent potential of coadministration of iRGD with multistage-responsive nanoparticles for enhancing drug delivery efficiency and overcoming the 4T1 breast cancer.

DenTimol as A Dendrimeric Timolol Analogue for Glaucoma Therapy: Synthesis and Preliminary Efficacy and Safety Assessment

In this work, we report the synthesis and characterization of DenTimol, a dendrimer-based polymeric timolol analog, as a glaucoma medication. A timolol precursor ( S)-4-[4-(oxiranylmethoxy)-1,2,5-thiadiazol-3-yl]morpholine (OTM) was reacted with the heterobifunctional amine polyethylene glycol acetic acid (amine-PEG-acetic acid, M_n = 2000 g/mol) via a ring opening reaction of an epoxide by an amine to form the OTM-PEG conjugate. OTM-PEG was then coupled to an ethylenediamine (EDA) core polyamidoamine (PAMAM) dendrimer G3 to generate DenTimol using the N-(3-(dimethylamino)propyl)- N'-ethylcarbodiimide hydrochloride (EDC)/ N-hydroxysuccinimide (NHS) coupling reaction. MALDI mass spectrometry, ¹H NMR spectroscopy, and HPLC were applied to characterize the intermediate and final products. Ex vivo corneal permeation of DenTimol was assessed using the Franz diffusion cell system mounted with freshly extracted rabbit cornea. The cytotoxicity of DenTimol was assessed using the WST-1 assay. Our results show that DenTimol is nontoxic up to an OTM equivalent concentration of 100 μM. DenTimol is efficient at crossing the cornea. About 8% of the dendrimeric drug permeated through the cornea in 4 h. Its IOP-lowering effect was observed in normotensive adult Brown Norway male rats. Compared to the undosed eye, an IOP reduction by an average of 7.3 mmHg (∼30% reduction from baseline) was observed in the eye topically treated with DenTimol (2 × 5 μL, 0.5% w/v timolol equivalent) in less than 30 min. Daily dosing of DenTimol for a week did not cause any irritation or toxicity as confirmed by the histological examination of ocular tissues, including the cornea, ciliary body, and retina.

Co-delivery of dihydroartemisinin and docetaxel in pH-sensitive nanoparticles for treating metastatic breast cancerviathe NF-κB/MMP-2 signal pathway

Metastasis is a major barrier in cancer chemotherapy. Prolonged circulation and rapid, specific intracellular drug release are two main goals in the development of nanoscale drug delivery systems to treat metastatic breast cancer. In this study, we investigated the anti-metastasis effect of docetaxel (DTX) in combination with dihydroartemisinin (DHA) in metastatic breast cancer 4T1 cells. We synthesized a pH-sensitive material 4-arm-PEG-DTX with a hydrazone bond and used it to construct nanoparticles that co-deliver DTX and DHA (D/D NPs). The D/D NPs had a mean size of 142.5 nm and approximately neutral zeta potential. The pH-sensitive nanoparticles allowed acid-triggered drug release at the tumor site, showing excellent cytotoxicity (IC50 = 7.0 μg mL⁻¹), cell cycle arrest and suppression of cell migration and invasion. The mechanisms underlying the anti-metastasis effect of the D/D NPs involved downregulation of the expression of p-AKT, NF-κB and MMP-2. Therefore, D/D NPs represent a new nanoscale drug delivery system for treating metastatic breast cancer, responding to the acidic tumor microenvironment to release the chemotherapeutic drugs.

Co-delivery DTX and DHA as acid-sensitive nanoparticles to exert synergistic effects for metastatic breast cancer therapy.